Macro etching evaluates samples cut from weld coupons to check for weld quality. An inspector must grind and polish the cut face of the sample before etching the surface with a chemical reagent. This process makes the weld area, heat-affected zone (HAZ), and base metal more easily distinguishable and exposes the microstructure and flow lines in the material. Inspectors examine the etched surface for discontinuities, cracks, porosity, weld profile, lack of sidewall fusion, weld size, lack of penetration, and other material characteristics. The macro etch test can provide data for weld procedure qualification, failure analysis, routine quality checks, and welder qualification testing.